Some infections are spread through the air we breath out, like Covid19.  Some are spread from feces to hand to mouth, like hepatitis A or norovirus or dysentery.  Refusing to wear a mask during the Covid19 epidemic is like refusing to wash hands after toiletting during a hepatitis outbreak.  This is basic courtesy and common sense.  If you don’t get that, I don’t want to eat the food you handle or share the air you exhale.  Please wear masks in public until this epidemic subsides.  And in the future, please use the mask whenever you have symptoms of cold or flu.  Thank you for your consideration.